Projectile using shape-memory alloy to improve impact energy transfer

Abstract

A projectile having an active component of shape-memory alloy that will not distort the projectile's shape or balance during launch or flight but which will alter the projectile shape upon impact to increase energy transfer efficiency against targets is disclosed.

What is claimed is: 
     
       1. A projectile, comprising: a core; and   deforming means of shape-memory alloy in operative contact with said core, said deforming means altering the geometric shape of said core upon impact of the projectile due to shape-memory effect to improve the impact energy transfer of the projectile.   
     
     
       2. A projectile as in claim 1 wherein said shape-memory alloy has a martensitic state and an austenitic state, said deforming means being dimensionally deformed prior to impact while said shape-memory alloy is in its martensitic state, a change from its martensitic state to its austenitic state recovering said deforming means upon impact to its non-deformed dimension to alter the geometric shape of said core. 
     
     
       3. A projectile as in claim 2 wherein said deforming means is generally contained within said core. 
     
     
       4. A projectile as in claim 3 wherein said core has a longitudinal axis, said deforming means comprising a rod that is dimensionally deformed into general axial alignment with said longitudinal axis when said shape-memory alloy is in its martensitic state, said rod recovering to be out of column when said shape-memory alloy is in its austenitic state. 
     
     
       5. A projectile as in claim 2 wherein said core has a longitudinal axis and includes a nose portion and said deforming means comprises a cap that is complementary to and in contact with said nose portion, said cap being symmetrical about said longitudinal axis with respect to said nose portion when said shape-memory alloy is in its martensitic state, said cap being asymmetrical about said longitudinal axis with respect to said nose portion when said shape-memory alloy is in its austenitic state. 
     
     
       6. A projectile as in claim 2 wherein said core has a longitudinal axis and includes a nose portion and said deforming means comprises a cap that is complementary to and in contact with said nose portion, said deforming means further including a rod in general axial alignment with said longitudinal axis and having a first length, when said shape-memory alloy is in its martensitic state, said rod reducing in length when in its austenitic state. 
     
     
       7. A projectile as in claim 2 wherein said core has a longitudinal axis and includes a cutting head, said deforming means being contained within said cutting head and being in general axial alignment with said longitudinal axis, a change of said shape-memory alloy from its martensitic to its austenitic state radially expanding said cutting head with respect to said longitudinal axis, increasing the cross-section of the cutting head. 
     
     
       8. A projectile as in claim 2 wherein said core has a longitudinal axis and further including a skin surrounding said core, said deforming means being positioned between said core and said skin, a change in said shape-memory alloy from its martensitic to its austenitic state radially compressing said core about said longitudinal axis to improve armor penetration characteristics of the projectile. 
     
     
       9. A projectile as in claim 2 wherein said deforming means contains voids, said voids enhancing the recovery of said deforming means beyond the inherent recovery of the shape-memory alloy comprising said core if said voids were not present. 
     
     
       10. A projectile of shape-memory alloy wherein said shape-memory alloy has a martensitic state and an austenitic state, said projectile being dimensionally deformed prior to impact while said shape-memory alloy is in its martensitic state, a change from its martensitic state to its austenitic state recovering said projectile upon impact due to shape-memory effect to its non-deformed dimension to alter the geometric shape of the projectile to improve the impact energy transfer of the projectile. 
     
     
       11. A projectile as in claim 10 wherein said projectile contains voids and said voids enhancing the recovery of said projectile beyond the inherent recovery of the shape-memory alloy comprising said projectile if said voids were not present. 
     
     
       12. A projectile, comprising: a core having a longitudinal axis; and   deforming means of shape-memory alloy being in operative contact with said core and being generally contained within said core, said shape-memory alloy having a martensitic state and an austenitic state, said deforming means comprising a rod that is dimensionally deformed prior to impact into general axial alignment with said longitudinal axis when said shape-memory alloy is in its martensitic state, a change from its martensitic state to its austenitic state recovering said rod upon impact to its non-deformed dimension to be out of column to alter the geometric shape of said core due to shape-memory effect to improve the impact energy transfer of the projectile.   
     
     
       13. A projectile, comprising: a core having a longitudinal axis and including a cutting head; and   deforming means of shape-memory alloy being in operative contact with said core and being contained within said cutting head and being in general axial alignment with said longitudinal axis, said shape-memory alloy having a martensitic state and an austenitic state, said deforming means being dimensionally deformed prior to impact while said shape-memory alloy is in its martensitic state, a change from its martensitic state to its austenitic state recovering said deforming means upon impact to its non-deformed dimension, radially expanding said cutting head with respect to said longitudinal axis due to shape-memory effect, increasing the cross-section of the cutting head to improve the impact energy transfer of the projectile.